Sync execCommand() and queryCommand*() IDL with spec

Source/core/dom/Document.idl

Index: Source/core/dom/Document.idl
diff --git a/Source/core/dom/Document.idl b/Source/core/dom/Document.idl
index 4c819aeaa3f2bcef6d0a76be646918d9877d8b26..db4f4ed42f5d5a4cb6a8e5bfb171c1a146b4d21a 100644
--- a/Source/core/dom/Document.idl
+++ b/Source/core/dom/Document.idl
@@ -93,15 +93,12 @@ interface Document : Node {
 
     // Common extensions
     [CustomElementCallbacks]
-    boolean            execCommand([Default=Undefined] optional DOMString command,
-                                   [Default=Undefined] optional boolean userInterface,
-                                   [TreatUndefinedAs=NullString, Default=Undefined] optional DOMString? value);
-
-    boolean            queryCommandEnabled([Default=Undefined] optional DOMString command);
-    boolean            queryCommandIndeterm([Default=Undefined] optional DOMString command);
-    boolean            queryCommandState([Default=Undefined] optional DOMString command);
-    boolean            queryCommandSupported([Default=Undefined] optional DOMString command);
-    DOMString          queryCommandValue([Default=Undefined] optional DOMString command);
+    boolean execCommand(DOMString command, optional boolean showUI = false, optional DOMString value = "");
+    boolean queryCommandEnabled(DOMString command);
+    boolean queryCommandIndeterm(DOMString command);
+    boolean queryCommandState(DOMString command);
+    boolean queryCommandSupported(DOMString command);
+    DOMString queryCommandValue(DOMString command);
 
     // Moved down from HTMLDocument
              [TreatNullAs=NullString, CustomElementCallbacks] attribute DOMString dir;